The present invention refers in general to equipments the be used for excavation, demolition or earthwork operations, and relates in particular to a quick coupling device for connecting a tool to a handling equipment, such as the articulated arm of an excavator, or similar.
Known devices that allow tools, such as buckets, cutters and demolisher hammers, to be quick coupled to the articulated arm of an excavator in different working phases during execution, earthwork or demolition operations, allow the time to substitute the tools to be reduced. In the most common case, these devices comprise a first support member connected to the free end of the articulated arm and a second support member connected to the tool, which support members can be mutually connected by mechanical coupling members that comprise a pair of generally parallel pins interposed between the aforesaid support members.
Some known quick coupling devices, such as for example that one described in GB-A-2 330 568, comprise movable hook members associated with the first support member, and therefore with the end of the handling arm, which are rotatably mounted in order to allow the aforesaid pins connected to the second support member to be grasped or released, rotation of the hook members being controlled by a hydraulic or mechanical control system.
Although these known devices allow the tools to be connected to an articulated handling arm to be replaced quickly, they have the drawback that they acquire clearances in the use, as a result of the wear the mechanical members of the coupling device are subjected to, because of the severe stresses the tools and the handling arm undergo in the use. These clearances cause the stability of the connection to be degraded in the time, and originate annoying vibrations that can cause a progressive damaging of the tools and of the handling arm up to jeopardize their correct operation.
Moreover, these known devices have relevant sizes in the axial direction of the handling arm and are remarkably cumbersome, which reduces their versatility of use and might negatively modify geometry and possibility of movement of the tools.
In particular, the invention relates to a quick coupling device for connecting a tool to a handling equipment, such as the arm of an excavator, comprising a first support member adapted to be connected to an end of said arm, and a second support member adapted to be fastened to the tool to be connected to said arm, wherein said support members are mutually engageable as a result of a relative movement along an axis of coupling generally transverse to the end of said arm, each support member comprising two opposed coupling formations having a double inclination so as to converge towards the axis of coupling both along the direction of mutual connection of the support members and with respect to a plane transverse to the axis of coupling, one of the support members including movable holding means which are adapted to engage at least a corresponding seat of the other support member in the mutually coupled configuration of the support members in order to cause mutual locking of the two support members.
EP-A-1 353 011 discloses a coupling device of the type defined above, which is adapted to allow a working tool to be removably connected to a working machine. The device comprises a first support member in the form of a trapezoidal plate, connected to the machine, and a second support member, having a seat which shape correspond to said plate, connected to the tool. The side edges of the first support member, which are tapered with respect to the axis of coupling in the second portion and the cross-sectional of which is V shaped, are intended to engage side guide formations the shape of which corresponds to that of a second support member. Owing to the shape of the side edges of the plate and the seat, which allow the first and a second support member to be kept in predetermined mutual positions, the plate of the first support member cannot be pushed against the counter surface of the seat. Moreover, the second support member, at the narrow end of the trapezoidal seat, is provided with an abutment crosspiece that constitutes an end-of-stroke member, and that limitates therefore the introduction of the first member in the respective seat. In this manner, the plate of the first member can be inserted into the seat of the second member only until it interferes with such a crosspiece, which prevents the possibility of recovering clearances between the two support members. Because of the structure of the device of this document, therefore, clearances between the side edges of the first support member and the respective guide formations of the second member may originate, that can not be easily recovered and that, in the use, may cause vibrations to arise.